throttle cable solved! Thanks guys!

[southwind25]

Ok Birkin (and perhaps others?) owners....heres a question:

 

i knew my throttle was sticking a bit and wouldnt fully return to it's stops. So i am looking at the problem and find the spring return on the carb end isnt working right, thats an easy fix...but i couldnt believe the way this thing works!

On the gas pedal end...the cable housing is connected to the pedal!!

HUH??

and the cable is held still.

On the carb end it is normal where the cable housing is held still and the cable goes thru a normal lever.

 

this is wacky!! t seems to sorta defy physics a bit and i have never seen a throttle with a moving cable housing on purpose.

is this right?

further the cable housing rubs through a hole which i am afraid will soon rub through the housing cover and housing?

 

is this the way the birkin is made? or did someone screw up the build? anyone have a picture of there setup?

[slomove]

No, that is normal for some older Birkins and does not defy physics.

Well, admittedly in most other car installations it is the other way with a fixed cable sheath and only the core moves.

 

But, the way you (and I) have it has the advantage that the cable can be shorter, routed closer to the scuttle, away from the hot parts and eliminating much of the clutter around the engine.

 

Anyway, if this is done properly and the minor movement of the cable sheath is allowed it works absolutely fine and has no other disadvantage. Actually, when I changed from Webers to throttle bodies I rebuilt the linkage to keep this nice feature.

 

Don't worry, the reinforced cable won't chafe in the hole through the pedal box. At least it did not in 4 years for my car. I did however fabricate an additional plastic guide within the pedal box but don't know if this is really necessary.

 

Gert

 

http://www.usa7s.com/aspnetforum/upload/752973558_WithFilterFront.jpg

[southwind25]

Ok,,,so it.s not so crazy..thanks Gert, and i appreciate the picture!

but i will try and make up some kind of sleeve so it has a better wear in that little thru-hole without binding either shouldnt be hard to do. .

 

 

 

[Davemk1]

That is more or less how my Birkin is set up. The inner cable is fixed and the housing floats. You are right that the housing rubs against the pedal box hole it passes through but mine has a delrin guide that keeps it from binding or abrading the housing. It helps to make sure that the first half of the cable run from the pedal is clear an also the the cable to move naturally when you push the pedal.

 

Mine didn't work that well until I replaced the cable and housing. Being in the bicycle biz I naturally used bike cables for the job. They work much, much better than the crap Birkin cable. I used an inner cable that has a teflon covering and an outer housing that has a teflon lining and there is now much bette throttle control as you can make very small movements with little to no stiction. It also takes less effort to push down the pedal and it returns all the way very quickly. If you want to get extra fancy you can use bike gear cable and housing. The cable is about the same as brake cable but the housing is a good bit different. Most housing is like the stuff on the Birkin...........it's a coiled wire with a rubber coating over the outside. The coiled wire compresses a good bit under pressure and can give the cable action a good bit of slop. Gear cable on the other hand uses metal but it's not coiled. Gear housing uses small metal rods running lengthwise and arranged on a circle to make a tube. This tube is then lined with teflon and covered with plastic on the outside. This in done on bicycles to give very precise shifting. It also works very well as throttle cable for the same reason. The housing doesn't compress.

 

Good stuff.

 

Dave

[southwind25]

Wow,,,i had no idea...sounds like good stuff. We have a good bicycle dealer close to us. does this have a trade name or should i ask for a brand name? or just print off your reply and ask for help?

 

dont get me wrong i am pretty good mechanically..but this car is a learning experience!

 

got the brake lights fixed too...it's all going well.

[Davemk1]

Any quality bike cable and housing should be fine. Most cable is made by the same company and then sold under a number of different names. If you want to be 100% sure you've got good stuff get Shimano............that's always a safe bet.

 

Dave

[Birkin42]

Most bicycle shops also stock housings in bulk and can sell it by the foot. Get the best teflon lined ones they carry. Don't forget to ask for the metal end caps for the housings as well. I'd go with Shimano teflon inner cables like Dave recommended. I find they are the best, at least for bicycles. The teflon Shimano cables have a thin black/graphite coloured coating over the stainless steel cable.

 

Jack

[Davemk1]

Most bicycle shops also stock housings in bulk and can sell it by the foot. Get the best teflon lined ones they carry. Don't forget to ask for the metal end caps for the housings as well. I'd go with Shimano teflon inner cables like Dave recommended. I find they are the best, at least for bicycles. The teflon Shimano cables have a thin black/graphite coloured coating over the stainless steel cable.

 

Jack

 

Very good point about the ferrules on the housing ends. They make the housing seat well and take out slop as well as providing a seal to crap getting in.

 

Dave